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by ejolson
Wed Sep 18, 2019 5:35 pm
Forum: General discussion
Topic: Power over Ethernet and Fan
Replies: 9
Views: 163

Re: Power over Ethernet headed

"Someone" already has. "Someone" is RPT, and it's called the Raspberry Pi PoE HAT. :lol: :roll: I was aware the POE hat has a inbuilt fan. That's why I wondered whether those pins could be used more simply just for the sake of powering a fan. I took a look at the PoE HAT that I have. I don't think ...
by ejolson
Wed Sep 18, 2019 4:16 pm
Forum: General discussion
Topic: stuck in wifi - Debian wheezy
Replies: 7
Views: 195

Re: stuck in wifi - Debian wheezy

To the person making the original post, is it possible you are trying to run two copies of wpa_supplicant? I think the reason some people are still using Raspbian Wheezy is because they were following tutorials that broke when systemd was made default. I recently installed 32-bit antiX Linux on a nu...
by ejolson
Wed Sep 18, 2019 3:48 pm
Forum: General discussion
Topic: Power over Ethernet and Fan
Replies: 9
Views: 163

Re: Power over Ethernet headed

I suppose someone could design a HAT or other add-on board that would take power from those pins and convert it to something a fan could run on, but it would still only work if the Pi was connected to a PoE switch. "Someone" already has. "Someone" is RPT, and it's called the Raspberry Pi PoE HAT. :...
by ejolson
Wed Sep 18, 2019 3:33 pm
Forum: General discussion
Topic: Power over Ethernet and Fan
Replies: 9
Views: 163

Power over Ethernet and Fan

I was reading the thread

https://www.raspberrypi.org/forums/view ... 2&t=251977

and wondered if it is possible to power a fan by connecting it to the POE header. Does anyone know?
by ejolson
Wed Sep 18, 2019 4:42 am
Forum: General discussion
Topic: VPN
Replies: 6
Views: 149

Re: VPN

Which one is free lol Both are free. I would use WireGuard or IPsec for hardening a local area network and either OpenVPN or an ssh tunnel to connect remote through the Internet. I recently tested WireGuard on a number of different Raspberry Pi models and was favorably impressed. Details are at htt...
by ejolson
Wed Sep 18, 2019 3:59 am
Forum: Mathematica
Topic: Bugs in Mathematica on Raspberry Pi 3?
Replies: 2
Views: 9329

Re: Bugs in Mathematica on Raspberry Pi 3?

I wrote some Mathematica code reading data fast from a TCP device. It works reliably under 10.3.1 but not version 11 or 12. Any idea idea how to install version 10.3 now? "sudo apt-get install wolfram-engine" installs version 12.0.1 and "apt-cache madison wolfram-engine" only shows that version as ...
by ejolson
Tue Sep 17, 2019 5:35 pm
Forum: General discussion
Topic: trying to buy more than 1 pi zero
Replies: 18
Views: 477

Re: trying to buy more than 1 pi zero

You can go to places like micro center, you can keep buying one for $5 but you have to go around and get back in line. if the cashier is nice they will ring up to 2 separate. or if you have multiple accounts you can buy one for 2 separate accounts etc work/home. Over all I think @ $5 each... they a...
by ejolson
Tue Sep 17, 2019 4:46 pm
Forum: General discussion
Topic: trying to buy more than 1 pi zero
Replies: 18
Views: 477

Re: trying to buy more than 1 pi zero

I didn't understand. Sorry if I have offended anyone. Unfortunately, the rationing of Pi Zero computers is frustrating for many. As with bread in former communist countries, when anything is produced to be sold below market equilibrium prices, shortages and rationing follow. What I find strange is ...
by ejolson
Tue Sep 17, 2019 2:34 pm
Forum: General discussion
Topic: Looking for a mounting solution for RPi (in case)
Replies: 12
Views: 409

Re: Looking for a mounting solution for RPi (in case)

Each individual Pi will be deployed to a different customer location. We're pretty locked in with the modular case we're using now because it allows us to block access to everything but the ethernet & power ports so that customers aren't tempted to mess with them. At my desk, I assemble them, insta...
by ejolson
Tue Sep 17, 2019 4:07 am
Forum: Advanced users
Topic: Raspberry Pi distributed computer project
Replies: 8
Views: 408

Re: Raspberry Pi distributed computer project

RedPanther wrote:
Mon Sep 16, 2019 4:34 pm
If you've made it this far into my build, I recently went through some system upgrades.
It looks like things are coming together. Are you are making your own case? What is the case made of? Is it made from wood? Or is it made with some special type of plastic?
by ejolson
Tue Sep 17, 2019 2:06 am
Forum: Networking and servers
Topic: Generic storage benchmark on RPI
Replies: 2
Views: 94

Re: Generic storage benchmark on RPI

Hi Folks, There's a lot of disk benchmarking done for SSD / SD etc and other storage using CrystalDiskMark which runs on PC. Is there an equivalent running natively on RPI raspian? It will be a better 'whole-system' test for storage performance that just testing the media on a PC without taking int...
by ejolson
Tue Sep 17, 2019 1:39 am
Forum: General discussion
Topic: A Pi Pie Chart
Replies: 112
Views: 11560

Re: A Pi Pie Chart

I'm somewhat disappointed that switching to 64-bit didn't solve the performance problems with newer compilers and merge sort. I clicked with my mouse and created an Amazon EC2 instance with 4 Graviton processors running 64-bit ARM Ubuntu Linux. For reference this is an a1.xlarge instance with 8GB R...
by ejolson
Tue Sep 17, 2019 12:09 am
Forum: General discussion
Topic: Why moving to 64bit?
Replies: 259
Views: 17873

Re: Why moving to 64bit?

Once I added -mcpu=cortex-a72, sysbench gets 10x faster in the 32-bit case to become on par with aarch64. I have tried to reproduce this result here but was unable. My understanding is that the Cortex-A72 running in 32-bit mode does not have any 64-bit registers and so can't perform any 64-bit divi...
by ejolson
Mon Sep 16, 2019 9:48 pm
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 13
Views: 1812

Re: Pi4 Sysbench results

dom wrote:
Mon Sep 16, 2019 9:38 pm
bl 0 <__aeabi_uldivmod> ?
Hm. I must be blind. It seems I missed that. So why is it running so fast? [Edit: Okay, the version I compiled isn't running fast. What's going on with the claim that -mcpu=cortex-a72 makes sysbench run fast in 32-bit mode?]
by ejolson
Mon Sep 16, 2019 8:12 pm
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 13
Views: 1812

Re: Pi4 Sysbench results

My conjecture is that the unusually fast run time results from a compiler aggressively optimizing a trivial benchmark. Performing objdump -S with debugging information turned on yields 000000ac <cpu_execute_event>: for(c=3; c < max_prime; c++) ac: e3003000 movw r3, #0 b0: e3403000 movt r3, #0 { b4:...
by ejolson
Mon Sep 16, 2019 8:07 pm
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 13
Views: 1812

Re: Pi4 Sysbench results

sysbench --num-threads=4 --test=cpu --cpu-max-prime=20000 --validate run WARNING: the --test option is deprecated. You can pass a script name or path on the command line without any options. WARNING: --num-threads is deprecated, use --threads instead sysbench 1.0.11 (using system LuaJIT 2.1.0-beta3...
by ejolson
Mon Sep 16, 2019 7:33 pm
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 13
Views: 1812

Re: Pi4 Sysbench results

sysbench --num-threads=4 --test=cpu --cpu-max-prime=20000 --validate run WARNING: the --test option is deprecated. You can pass a script name or path on the command line without any options. WARNING: --num-threads is deprecated, use --threads instead sysbench 1.0.11 (using system LuaJIT 2.1.0-beta3...
by ejolson
Mon Sep 16, 2019 7:29 pm
Forum: General discussion
Topic: ARMv8 32-bit mode and 64-bit division
Replies: 5
Views: 246

Re: ARMv8 32-bit mode and 64-bit division

Are you sure your original reported Pi 3B+ run times were accurate? Since Raspbian Buster includes gcc-4.9, gcc-5.5, gcc-6.5 and gcc-7.3 I installed and tried them all. Using variations of -mcpu=cortex-a53 -mfpu=neon-fp-armv8 -mfloat-abi=hard -mneon-for-64bits -Os all run times are greater than 30 ...
by ejolson
Mon Sep 16, 2019 6:46 pm
Forum: General discussion
Topic: ARMv8 32-bit mode and 64-bit division
Replies: 5
Views: 246

Re: ARMv8 32-bit mode and 64-bit division

Do you remember what the compiler settings were that you used? I read through the rest of that thread and found the suggestion -march=native -Os -mneon-for-64bits I also tried -march=native -O3 -mneon-for-64bits -mcpu=cortex-a72 -mfpu=neon-fp-armv8 -mneon-for-64bits -Os -mcpu=cortex-a72 -mfpu=neon-...
by ejolson
Mon Sep 16, 2019 6:24 pm
Forum: General discussion
Topic: ARMv8 32-bit mode and 64-bit division
Replies: 5
Views: 246

Re: ARMv8 32-bit mode and 64-bit division

Your results look entirely reasonable to me. In your post https://www.raspberrypi.org/forums/viewtopic.php?p=1292430#p1292430 you obtain the runtime pi3+ (Cortex A53 in 32 bit mode, gcc 7.3, 1.4GHz) Found a total of 664579 primes (64-bit) real 0m14.691s user 0m14.680s sys 0m0.000s for the Pi 3B+ in...
by ejolson
Mon Sep 16, 2019 5:41 pm
Forum: General discussion
Topic: ARMv8 32-bit mode and 64-bit division
Replies: 5
Views: 246

Re: ARMv8 32-bit mode and 64-bit division

I'll be updating this thread with a new table containing new details and runtimes as well as the Pi 4B in the next post. I have run the following program #include <stdio.h> #include <math.h> #include <stdint.h> #define N 10000000 static INT prime[1000000]; static int count=0; static int isprime(INT...
by ejolson
Mon Sep 16, 2019 5:29 pm
Forum: General discussion
Topic: Pi4 Sysbench results
Replies: 13
Views: 1812

Re: Pi4 Sysbench results

I wouldn't say sysbench CPU is useless, but acknowledge that a prime number sieve is not representative of everyday desktop usage. I missed the sysbench discussion 1.5 years ago on this forum, but I believe I resolved any open questions here: https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=...
by ejolson
Mon Sep 16, 2019 5:11 pm
Forum: General discussion
Topic: CrystalDiskMark for Linux
Replies: 2
Views: 101

Re: CrystalDiskMark for Linux

Hi, I connected my Raspberry Pi 4 to an external hard drive and want to test the speed of it. What would be an alternative to CrystalDiskMark but for Linux? Thanks!! Please check the thread https://www.raspberrypi.org/forums/viewtopic.php?f=36&t=251789 which asked the same question a few days ago.
by ejolson
Mon Sep 16, 2019 4:59 pm
Forum: General discussion
Topic: ARMv8 32-bit mode and 64-bit division
Replies: 5
Views: 246

ARMv8 32-bit mode and 64-bit division

There was a long running thread here that comes up easily on web searches comparing the speed of the Raspberry Pi to some common PCs. In light of this post, that old thread appears to contain some incorrect assumptions about running an ARMv8 processor in 32-bit mode. In particular, it seems that spe...
by ejolson
Sun Sep 15, 2019 9:44 pm
Forum: Networking and servers
Topic: Generic storage benchmark on RPI
Replies: 2
Views: 94

Re: Generic storage benchmark on RPI

Hi Folks, There's a lot of disk benchmarking done for SSD / SD etc and other storage using CrystalDiskMark which runs on PC. Is there an equivalent running natively on RPI raspian? It will be a better 'whole-system' test for storage performance that just testing the media on a PC without taking int...

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